Property  of  the  United  Mites  Governn 


Circular  No    82. 


l-.u.-.l  .1 


United  States  Departmenl  of  Agriqul 

BURKAU     OK    ENTOMOLOGY, 
1      0     HOWARD     I  >nd  Chief  ..(  Hurcau. 


PUfHOLI    I2MUB1    TO    MKMKI)   CYPRESS   IN    THE    sol  III 

vm>  BULP  G  I  1 1  i  8. 

B]     \.    I'.    HOPXJKB,    , 

In  Charge  of  Fonti  i>>^><t  I" 

Pursuant  to  certain  complaints   of  Beriouajnj 
insects  to  girdled  cypress  timber  in  the  South  Atlantic  and 
the  Bureau  of  Entomology  began  of  experiments  and  investiga- 

tions with  Bpecial  trees  girdled  on  definite  dates  in  •■very  month  of  tin- 
year,  as  well  as  with  those  girdled  in  regular  operations  at  known  dates 

or  periods,  to  determine  whether  Ol  not  there  was  any  important  rela- 
tion between  the  month  or  time  of  year  the  trees  were  girdled  ami  Bub- 
BOqnent  injuries. 

This  w..rk  was  personally  conducted  by  specialists  of  the  Bureau  in 
cooperation  with  cypress  manufacturers  in  southeastern  North  Carolina, 
southern  South  Carolina,  southeastern  Georgia,  western  Florida,  ami 
southern  Louisiana.  It  was  begun  in  the  Bpring  of  1903  ami  continued 
until  December,  1904.  Over  300  trees  were  examined,  and  observations 
made  on  practically  all  of  the  different  Bpeciesof  insert.- which  are 
in  any  manner  associated  with  injury  to  the  wood  and  hark  of  living, 
dying,  and  felled,  as  well  as  girdled,  cypn 

RESULTS   OF    INVESTIGATIONS. 

'l'h'  principal  injury  to  the  wood  of  standing  girdled  cypress  was 
found  to  consist  of  pinholes  in  the  Bapwood  and  heartwood  caused  by 

two  classes  Of  small  WOOd-boring  hectic.-,  called  timher  hectics,  amhrosia 
beetles,  pin  borers,  "pin  worms.'"  etc.  They  bore  the  so-called  pin- 
holes in  the  wood  as  place-  to  deposit  egU'>  and  rear  their  brood.-,  and 
the  latter,  when  fully  developed,  leave  the  wood  and  By  to  other  trees 
to  repeat  the  pro 

One  of  these  el..  WOOd-boring   beetles  is  represented   by  small. 

short,  cylindrical,  reddish  beetles  one-eighth  to  one-tenth  of  an  inch  in 
length,  which  are  exclusively  Bapwood  borers.  U  i  rule  they  are  not 
common   in    girdled   trees,  but    are  abundant   in  logs  from  living   I 

The  other  class  is  represented  by  elongate,  slender,  reddish,  cylin- 
drical beetles  three-eighths  of  an  inch  in  length,  which  oft.n  extend 
their  borings  deep  into  the  heartwood  and  are  often  common  and  quite 


injurious  to  both  girdled  and  felled  trees.  One  species  of  this  latter  class 
causes  more  damage,  perhaps,  than  all  of  the  many  other  insects  which 
have  been  found  boring  in  the  wood  of  girdled  trees.  It  is  known  tech- 
nically as  Platypus  compositus  Say,  and  may  be  distinguished  from 
other  cypress  pin-borers  by  the  English  name  "  girdled-cypress  pin- 
borer,"  or  Pan  American  Platypus.     (See  fig.  1.) 

The  facts  and  evidence  of  immediate  practical  importance  may  be 
briefly  stated  as  follows:  Trees  girdled  in  March,  April,  October,  and 
November  were  not  at  all  or  but  slightly  damaged  by  the  girdled-cypress 
pin-borer,  while  those  girdled  in  .May,  June,  July,  and  September  were 
more  or  less  seriously  damaged.  There  were  indications  that  trees 
girdled  in  August  were  not  damaged  as  badly  as  those  girdled  in  July 


Fig.  ].— Work  of  ambrosia  beetle?  in  oak:  a,  Monarthrum  mali  and  work;  b.  Platypus  compotitus 
and  work:  c,  bark;  rf,  sap  wood;  e,  beartwood:  /.  character  of  work  in  lumber  from  injured 
log.     (Author's  illustration.) 

and  September ;  also,  that  trees  girdled  from  December  to  February 
were  not  seriously  affected.  It  was  found  that  local  factors  and  con- 
ditions had  an  important  bearing  on  whether  or  not  injury  resulted  from 
girdling  at  given  dates.  In  some  localities  there  was  practically  no 
injury  to  trees  girdled  on  any  of  the  dates.  In  other  localities  some  of 
the  trees  girdled  on  a  given  date  would  be  badly  damaged  while  others 
would  show  no  trace  of  injuries.  The  absence  of  injuries  in  the  former 
localities  may  have  been  due  to  the  presence  of  a  limited  number  of  the 
insects,  or  to  their  being  attracted  to  felled  trees  in  preference  to  the 
standing  girdled  ones,  or  to  some  other  unknown  causes.  The  attack 
on  individual  trees  is  evidently  due  to  individual  differences  in  the  trees 
themselves,  for  our  general  observations  indicate  quite  clearly  that 
certain  types  and  varieties  of  trees  of  the  same  species  are  more  resistant 


or  immune  to  their  inseol  enemies  while  othen  are  more  attractive 
to  them.  It  i~  well  kiuiuii  that  there  i-  a  marked  difference  in  the 
individual  characteristics  of  oypress  trees  in  any  given  locality,  and 
m  differenl  localities,  and  thai  there  is  also  marked  differ- 
ence among  a  large  number  of  trees  girdled  on  the  same  day  or  time  of 
year  in  the  results  obtained.  Some  will  die  quickly  and  dry  oul  rani  illy: 
smne  will  remain  alive  a  inueli  longer  time,  the  wood  remaining  moist 
and  becoming  discolored;  -nine  will  yield  beautifully  grained  lumber 
of  the  highest  grade;  while  others,  equally  as  sound,  will  yield  tough, 
-  grained,  ilull  lumber  "f  a  l<>w  grade.  These  conditions  are  do! 
due  entirely  to  the  character  <  t  the  work  <>f  girdling,  nor  to  accident, 
local  influences  of  soil,  etc.,  l>ut  largely  to  variations  which  produce 

more  or   less  distinct,  good   and   poor  natural    varieties.      Therefore  cer- 
tain trees  or  varieties  which  prove  to  be  especially  attractive  to  the  pin- 
borer,  no  matter  when  they  are   girdled,  may   be  attacked   and   more  or 
injured. 

The   girdled-cypress    pin-borer  must  have  moist   w 1  in  which   to 

excavate  its  burrows  and  develop  its  broods  of  young  and  will  unl 

attack  the  trees  after  they  have   been  dead  long  enough  for  the  wood  to 
me  dry.      It  evidently  prefers  to  attack  the  wood  of  felled  gum  and 

cypress.     Our  observations  indicate  that  living  trees  felled  '"  April  and 

August  offer  specially  attractive  conditions  for  infestation  l>y  this 
and  that  it  \yill  often  begin  to  enter  tin-  wood  within  a  few  days  after 
the  trees  arc  felled.  This  BUggestS  the  utilization  of  felled  tree-  as  traps 
to  attract  it  away  from  the  girdled  ones  and  at  the  same  time  facilitate 
the  destruction  of  the  broods  by  placing  the  logs  of  the  trap  trees  in 
water  after  they  have  become  thoroughly  infested  and  before  the  hroods 
of  adults  begin  to  emerge  and  fly. 

To  aeconiplish  this  the  trap  trees  felled  in  April  must  he  burned  or 
placed  in  water  during  the  following  June  and  those  felled  in  August 
treated  in  the  same  manner  in  October. 

RECOMMENDATIONS. 

I  leneral  recommendations  for  the  prevention  of  insect  injury  to  girdled 
Cypress  may  he  briefly  stated  as  follows: 

First. — Conduct  the  principal  girdling  operations  in  March.  April, 
October,  and  November,  or  either  in  the  former  or  latter  months  as  may 
seem  hest  from  the  local  conditions  and  relative  value  of  the  product  in 
each  locality.  October-girdled  trees  should  he  felled  and  lloated  or 
worked  up  within  one  year  to  avoid  injury  by  another  class  of  wood 
horers  which  attack  trees  after  they  have  I. ecu   dead  one  or  more  years. 

Second.  —  In  localities  where  it  is  known  that  the  insect  is  abundant 
and  injurious,  felled  trap  trees  may  he  provided  in  March  and  April, 
and  July  and  August,  say.  one  otherwise  worthless  gum  or  cypres.-  trap 
tree  for  each  fifty  to  seventy  tree.-  to  be  girdled  in  the  same  locality. 


Tiiii:: 

4  3  1262  09216  fc' 

Third. — If  it  is  desirable  to  girdle  trees  at  other  times  during  the 
summer  and  to  utilize  trap  trees,  these  latter  should  be  provided  a  week 
3?  more  ahead  of  the  girdling,  and  located  on  the  banks  of  streams, 
ponds,  or  pools,  where,  at  the  proper  time,  they  can  be  readily  rolled 
into  the  water. 

Fourth. — Trap  trees  should  never  be  provided  unless  it  is  quite  cer- 
tain that  they  will  be  placed  in  the  water  or  otherwise  destroyed  within 
two  or  three  months  after  they  are  felled  and  infested  by  the  insects, 
otherwise  they  may  contribute  to  a  greater  multiplication  of  the  insects 
and  increased  danger  of  serious  injury  to  the  girdled  trees. 

The  adoption  and  carrying  out  of  these  recommendations  should  be 
governed  in  each  locality  by  the  personal  observations  and  experience 
of  the  operators,  based  on  a  study  of  the  conditions  resulting  from  trees 
girdled  at  different  positively  known  dates  or  times  of  year,  and  also  on 
a  study  of  the  evidences  of  infestation  by  the  pin-borer  in  the  girdled 
trees  and  in  the  logs,  stumps,  slash,  etc.,  of  cypress,  gum,  and  other 
trees.  These  evidences  of  infestation  consist  of  the  greater  or  less  quan- 
tities of  fine,  whitish  boring-dust  on  the  bark  and  around  the  base  of  the 
trees  and  stumps,  under  the  logs,  etc.,  the  work  of  the  girdled-cypress 
pin-borer  and  its  class  being  distinguished  from  that  of  the  sapwood 
borers  by  the  prevalence  of  short  cylindrical  sections  of  adhering  dust 
expelled  from  the  holes. 

For  more  detailed  information  on  the  habits  of  wood-boring  insects 
and  the  character  of  injuries  caused  by  them  in  standing  and  felled 
trees,  lumber,  etc.,  the  reader  is  referred  to  the  Yearbook  of  the  United 
States  Department  of  Agriculture  for  1904,  pages  381  to  398. 

Approved : 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  D.  C,  December  19,  1906. 

O 


